Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
  • G01S5/0284—Relative positioning
  • G01S5/0289—Relative positioning of multiple transceivers, e.g. in ad hoc networks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
  • G01S5/0009—Transmission of position information to remote stations
  • G01S5/0018—Transmission from mobile station to base station
  • G01S5/0036—Transmission from mobile station to base station of measured values, i.e. measurement on mobile and position calculation on base station
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
  • Y02D30/00—Reducing energy consumption in communication networks
  • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

• This invention relates to a system and method for monitoring the location of a mobile network unit in a low-power, localised wireless communication network.
• any reference to a wireless communication network will be understood to mean specifically a low-power, localised wireless communication network unless otherwise specifically stated.
• the invention relates to wireless communication networks of the type that may operate on a very low power supply, typically no more than a few volts, and used for very short range communications typically of the order of less than 100m between components of the network.
• the present invention in no way relates to mobile telephony applications and those large scale, relatively high power wireless communication networks with potentially long transmission ranges (e.g. over 100m) between components but in fact relates solely to much smaller scale wireless network such as those found in an individual building or other similar type of structure.
• Wireless communication networks are becoming more and more popular due to the ease of installation, relatively inexpensive equipment and scalable nature of the wireless communication networks. These wireless communication networks may be installed in a building or other structure with the minimum of disruption to the inhabitants as the individual charged with the installation of the network does not have to spend significant amounts of time drilling holes for power or communications wiring in the structure and may quickly install a comprehensive network throughout the installation in a fraction of the time that it would take with the previous wired networks.
• the wireless communication networks comprise a number of fixed network units, a control unit with a processor and accessible memory and one or more mobile network units.
• the mobile network units communicate with the control unit, which may have a database that the user of the mobile network device wishes to populate with data from the mobile network device, through the network of fixed network modules.
• data is sent by the mobile network unit to the control unit via one or more of the fixed network units.
• the fixed network units cooperate with each other to provide a channel for the data to be transmitted to the control unit. It is not necessary to have fixed communication channels and data may follow a different route to the control unit each time.
• the mobile network unit is not restricted to transmitting messages from a single point and may transmit messages from anywhere throughout the network.
• ZigBee provides a relatively inexpensive way to transmit small packets of data from a mobile network unit to a control unit. Due to the fact that ZigBee limits itself to small packets of data, the apparatus used for the fixed network units and the mobile network units may be relatively simple, and inexpensive. This helps to reduce the overall cost of installation of the network. Furthermore, due to the fact that the data packets are smaller than equivalent wireless communication networks, the computational burden and the communication overheads in the wireless communication network are also reduced significantly.
• system for monitoring the location of a mobile network unit comprising a localised wireless communication network having a control unit, a plurality of fixed network units and at least one mobile network unit,
• control unit further comprising a processor having accessible memory
• the mobile network unit further comprising a transmitter for transmitting an identification signal unique to that mobile network unit;
• the fixed network units each having a transceiver having means to receive the identification signal directly from a mobile network unit within a predetermined radius of the fixed network unit and indirectly from another fixed network unit, the fixed network units having means to determine the strength of the identification signal received directly from the mobile network unit, and the transceiver further comprising means to transmit the identification signal data and signal strength data to the control unit through the wireless communication network;
• control unit processor having means to collate the identification signal data and signal strength data received from a pair of fixed network units that received the identification signal directly from a mobile network unit and determine the location of the mobile network unit.
• a number of fixed network units may receive the signal and each of the network units that receive the initial identification signal will transmit that signal onwards to the control unit through the wireless network. In this way, as a number of the - A -
• the processor in the control unit to identify the location of the fixed network units and thereafter determine the location of the mobile network unit based on the fixed network units that received the initial identification signal. Furthermore, by determining the strength of the identification signal received by the fixed network unit, it is possible to more accurately determine the exact location of the mobile network unit in the wireless communication network.
• this feature may be used for a wide variety of disparate uses including the location of individuals or items of equipment carrying a mobile network unit or having a mobile network unit installed therein.
• the unit may be used to track the movements of one or more individuals within a structure, for example in a hospital environment it is possible to see whether an individual has been in a particular ward at a particular time of day and work practices may be monitored and improved as a result of the accurate tracking. This further enhances the usefulness of the known wireless communication networks.
• control unit processor has means to collate the signal identification data and signal strength data received from three fixed network units, each of which having received the identification signal directly from the mobile network unit, and determine the location of the mobile network unit.
• the wireless communication network further comprises a wireless personal area network (WPAN).
• WPAN wireless personal area network
• the WPAN is a ZigBee network.
• the ZigBee network is seen as a particularly preferred network for use with the present invention as it is relatively inexpensive to install in a structure and furthermore is relatively discreet.
• the ZigBee units themselves transmit very small packets of data and therefore require less power to transmit the signals and accordingly they will not have to be services often in order to change their power supply.
• the smal! data packet size means that the computational burden and the communication overhead in the system will be significantly reduced.
• a system in which the system is installed in a structure and in which the control unit has a floor plan layout of the structure stored in memory, the control unit processor having means to plot the location of a mobile network unit on the floor plan layout.
• the system may be installed in a building such as a hospital, prison, library, house, cruise liner or other structure so that it is an entirely self sufficient system that does not require further external equipment.
• this is seen as a particularly preferred embodiment of the invention as the position of the mobile network unit may be plotted on the floor plan and therefore the position of a mobile network unit may be known in relation to the actual layout of the structure in which it is installed which will facilitate quick and simple determination of its location in the structure.
• control unit processor has means to plot the movement of a mobile network unit in the structure over time.
• the control unit processor has means to plot the movement of a mobile network unit in the structure over time. By plotting the position of the mobile network unit over time, it will be possible to determine where in the structure the mobile network unit was at a particular given time and this will be particularly useful if for instance it is necessary that an individual should be in a particular location at a given time. By plotting the position of the mobile network unit, it is possible to determine where the mobile network unit was at any given time and accordingly where the individual carrying the mobile network unit was.
• the mobile network unit further comprises means to receive an identity code from a user and the identification signal transmitted by the mobile network unit is generated using the identity code of the user.
• the mobile network units themselves may be a generic unit such as a card holder device that may be worn by an employee who may insert their card in the card holder each time they are at work. In this way, the mobile network unit may be left in the premises and not removed from the premises.
• the mobile network unit may form part of a uniform or security clothing and the employee's identity card will provide the actual identification signal identifying features.
• the means to receive an identity codes from a user further comprises a card reader having means to read information from a data storage element on an identity card.
• the means to receive identity codes from a user further comprises a keypad having means to receive an identity code input on the keypad.
• the mobile network unit's transmitter transmits an identification signal periodically at predetermined intervals.
• the mobile network unit's transmitter transmits an identification signal in response to a mobile network unit operator's actions.
• the predetermined radius of the fixed network unit is of the order of a 5 meter radius.
• the predetermined radius of the order of 5 metres it is possible to ensure that a strong signal is received by the fixed network units so that they may accurately determine the strength of the signal to assist in positioning.
• the effective range may be chosen so that it will clearly receive signals transmitted from within a given distance. Signals may also be received from outside that given distance but they may be disregarded due to the very low signal strength indicating that they are almost certainly outside the chosen range of the fixed network unit.
• control unit In one embodiment of the invention there is provided a system in which data received by the control unit is time stamped.
• the processor has means to analyse the movement patterns of one of an individual mobile network unit or a group of mobile network units.
• the control unit has means to analyse the movement patterns of one or more mobile network units in a particular area.
• the control unit has means to generate an alarm based on predetermined irregular movement patterns of one or more mobile network units.
• a method of monitoring the location of a mobile network unit in a system comprising a localised wireless communication network having a control unit, a plurality of fixed network units and at least one mobile network unit, the mobile network unit having means to transmit an identification signal unique to that mobile network unit, the fixed network units each having a transceiver having means to receive the identification signal directly from a mobile network unit within a predetermined radius of the fixed network unit and indirectly from another fixed network unit, the fixed network units having means to determine the strength of the identification signal received directly from the mobile network unit, and the transceiver further comprising means to transmit the identification signal data and signal strength data to the control unit through the wireless communication network, the control unit having a processor and accessible memory, the method comprising the steps of:
• the mobile network unit transmitting an identification signal unique to that mobile network unit
• any of the fixed network units that receive that identification signal directly from the mobile network unit calculating the strength of the identification signal and transmitting the received identification signal data and signal strength data to the control unit;
• control unit processor collating the identification signal data received from a pair of the fixed network units that received the identification signal directly from a mobile network unit and determining the location of the mobile network unit.
• the method further comprises the step of the control unit receiving the identification signal data and signal strength data from three fixed network units that received the identification signal directly and thereafter determining the location of the mobile network unit by triangulating the identification signal data.
• the wireless communication network further comprises a wireless personal area network (WPAN) and in which the step of transmitting the identification signal to the control unit further comprises transmitting the identification signal through the WPAN.
• WPAN wireless personal area network
• the WPAN is a ZigBee network and the step of transmitting the identification signal to the control unit further comprises transmitting the identification signal through a ZigBee communications network.
• the control unit plots the movement of the mobile network unit in the structure overtime.
• the method further comprises the steps of the mobile network unit receiving an identity code from a user and generating the identity signal using the identity code of the user.
• the step of the mobile network device transmitting an identification signal unique to that mobile network unit further comprises the mobile network device transmitting the identification signal periodically at predetermined intervals.
• the method comprises the step of the mobile network device transmitting the identification signal in response to a mobile network unit operator's actions.
• the method comprises the step of the control unit analysing the movement patterns of one of an individual mobile network unit or a group of mobiie network units.
• the method comprises the step of the control unit analysing the movement patterns of one or more mobiie network units in a particular area.
• the method comprises the additional step of the control unit generating an alarm based on predetermined irregular movement patterns of one or more mobile network units.
• Figure 1 is a floor plan of a typical structure in which the system according to the invention is installed.
• Figure 2 is a diagrammatic representation of a ZigBee network
• the system 3 comprises a control unit 5, a plurality of fixed network units 7 and a plurality of mobile network units 9 all connected by way of a wireless communication network.
• the control unit 5 further comprises a processor (not shown) having an accessible memory (not shown).
• the mobiie network units 9 each comprise a transmitter (not shown) for transmitting an identification signal and each of the fixed network units 7 comprise a transceiver (not shown) having means to receive an identification signal from a mobile network unit and means to transmit the received identification signal data to the control unit 5 over the wireless communication network.
• the wireless communication network is a Wireless Personal Area Network (WPAN), in this case a ZigBee network.
• the fixed network units also are provided with means (not shown) to determine the strength of the identification signal and the fixed network units transmit data relating to the strength of the received identification signal to the control unit over the ZigBee network.
• the control unit 5 has means to collate the identification signal data and signal strength data relating to a mobile network unit received from the two or more fixed network units and determine the location of the mobile network unit.
• the fixed network units 7 are distributed throughout a structure, in this case a floor of a building.
• This floor may be the premises of a particular company and it is envisaged that the system may be spread out over a number of floors although only one of which is shown for the purpose of ciarity.
• the control unit 5 is stored in a server room 11 and there are a plurality of mobile network units also on that floor of the building. These mobile network units may be small units worn by certain employees to allow their whereabouts to be monitored or alternatively, these units may be located in equipment to allow the position of certain equipment to be monitored at any given time.
• the mobile network units transmit an identification signal periodically, for example, every 1, 5 or 30 seconds into the surrounding environment.
• the periodicity at which the identification signal is transmitted may be selectively chosen and what is important is that it is sufficient to allow the mobile network unit to be monitored effectively. Any of the fixed network units within a predetermined radius, in this case 5 metres, will detect that identification signal directly and they will determine the strength of the identification signal. Each of the fixed network units that received the identification signal directly will transmit the identification signal data and the strength signal data to the control unit 5 over the ZigBee network. The data may be transmitted through other fixed network units en route to the control unit.
• control unit 5 may be linked back to a further processing unit over the structures existing IT infrastructure, e.g. Ethernet over CAT5 cable or alternatively over a WiFi network. In this way, multiple control units in different areas may be connected back to a central server. In such instances, it will be understood that the control unit 5 will further comprise a ZigBee to Ethernet bridge or a ZigBee to WiFi bridge.
• This relaying of the identification signal data by the fixed network units is considered to be the fixed network units receiving the identification signal data indirectly.
• the fixed network unit receives the identification signal from a mobile network device, it is said to receive the identification signal directly.
• the fixed network device receives the identification signal from another fixed network device, it is said to have received the identification signal indirectly.
• Those fixed network units that receive the identification signal directiy will calculate the strength of the identification signal so that the control unit can use the information from two or more fixed network units to determine the location of a mobile network device.
• the mobile network unit 9(a) transmits an identification signal.
• This identification signal is detected and received directly by fixed network units 7(a), 7(b) and
• Each of the fixed network units 7(a), 7(b) and 7(c) determine the strength of the identification signal received. Then, once this has been achieved, the fixed network units
• 7(a), 7 ⁇ b) and 7(c) each transmit the identification signal data and signal strength data to the control unit 5 via at least some of the other fixed network units 7 ⁇ b), 7(c), 7 ⁇ d), 7(e), 7(f) and 7(g) in the wireless communication network.
• the signal strength data and identification data received by fixed network unit 7(a) is transmitted to the control unit 5 via fixed network unit 7 ⁇ b) and then to fixed network unit
• the fixed network unit 7(a) is said to have received the identification signal directly and the fixed network units 7(b), 7(c), 7 ⁇ d), 7 ⁇ e), 7(f) and 7(g) are said to have received that identification signal indirectly.
• the signal strength data and identification data received directly by fixed network unit 7(b) is transmitted to the control unit 5 via fixed network unit 7(c) and then to fixed network unit 7(d), and then to each of fixed network units 7 ⁇ e), 7(f) and 7 ⁇ g) in turn before being transmitted by fixed network unit 7(g) to the control unit.
• the fixed network unit 7(b) is said to have received the identification signal directly and the fixed network units 7(c), 7(d), 7 ⁇ e), 7(f) and 7(g) are said to have received that identification signal indirectly.
• the signal strength data and identification data received directiy by fixed network unit 7(c) is transmitted to the control unit 5 via fixed network unit 7(d) and then to fixed network unit 7(e), and then to fixed network unit 7(f) before being transmitted to fixed network unit 7(g) before being transmitted by fixed network unit 7(g) to the control unit 5.
• the fixed network unit 7(c) is said to have received the identification signal directly and the fixed network units 7(d), 7(e), 7(f) and 7(g) are said to have received that identification signal and signal strength data indirectly.
• the processor (not shown) of the control unit 5 may then determine the exact location of the mobile network unit in the structure.
• the control unit 5 has a floor plan of the building in memory and each piece of identification data and signal strength data is time stamped as it is received by the processor so that the control unit may effectively map the location of the mobile network unit over time on the floor plan.
• the fixed network units may be wireless devices with their own power supply such as a battery pack. Alternatively, it is envisaged that these fixed network units may operate on mains power and they could be plugged in to a standard socket in the building for convenience. In this way, the units would not have to be serviced in order to change the batteries every so often which heips to reduce the maintenance cost of such a system.
• the ZigBee network 12 comprises a plurality of static nodes 13 which are provided by the fixed network units, a plurality of mobile nodes 15 which are provided by the mobile network units and a gateway node 17, which is also provided by way of a fixed network unit.
• the gateway node 17 communicates directly with the control unit (not shown).
• Each of the static nodes obtains information from the mobile nodes and transmits this information through the ZigBee network via at least the gateway node to the control unit.
• each of the static nodes that receives information from a mobile unit will transmit that information through the network to the control unit so that an identification signal transmitted by a mobile node will not be sent by one static node but wiil be sent by each of the static nodes.
• the system is able to more accurately pinpoint the exact position of the mobile network unit/ mobile node so that their exact position may be determined rather than simply that they are within a predetermined radius of a static node. This is highly advantageous.
• the invention has been described throughout primarily with the goal of locating precisely an individual or a piece of equipment in a building at any given time and thereafter being able to plot the position of that individual, over time if required.
• the uses for the present invention extend far beyond simply the tracking of an individual or a piece of equipment to determine their exact position for logging purposes.
• the information may be used for a wide variety of purposes by using the spirit of the invention.
• the present invention could be used to track the movement and work practices of staff of a company, for example in a warehouse or an office floor over time. In this way, the productivity and time and flow management exercises may be performed to facilitate the operation of the company.
• the invention may be used to track the exact whereabouts of individual staff members which may be necessary to determine whether a certain employee was where they say they were at a particular time. For example, in an environment with valuable goods stored in certain locations, it is possible to determine what employee was in a particular area at a particular time or whether they were where they were supposed to be at a particular time. This provides greater accountability for the actions of the employees.
• control unit and the fixed network units have been described as entirely separate entities, the control unit may also be used to perform the function of a fixed network unit itself. Therefore, the control unit would have all of the properties of a fixed unit also.
• control unit may be located remotely from the mobile network units and the fixed network units. By remote what is meant is separated from or even located in another jurisdiction.
• a high-powered transceiver may be used to augment the wireless communications network specifically for communications with the control unit.
• the low powered localised wireless communication network has been described as a WPAN and more specifically a ZigBee WPAN.
• the wireless communication network could be another low- powered wireless communication network that supports a mesh network.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

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• 2007
  • 2007-02-12 EP EP07704533A patent/EP1982477A1/de not_active Ceased
  • 2007-02-12 IE IE20070083A patent/IES20070083A2/en not_active IP Right Cessation
  • 2007-02-12 WO PCT/EP2007/051356 patent/WO2007090903A1/en active Application Filing
  • 2007-02-12 US US12/223,839 patent/US8045498B2/en not_active Expired - Fee Related

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